Throughout time, people have invented symbols as visual short hand for some kind of other meaning. Some symbols have become universal for reasons of practicality, others are more local and only have meaning in a certain area or vary from area to area. Over time, symbols have become an important, but mysterious aspect of the Slender Man Mythos.This is an index of known Symbols in the Slender Man Mythos. If you believe something important has been omitted from this list, feel free to contact me.
 Operator Symbol The Operator Symbol

Description – A circle with an X through it.  Placement and angle of the X varies.  Bares a superfical resemblance to a symbol used for tensors in mathematics.

Origins – Marble Hornets

The original, most widely used symbol in the mythos.  The true purpose and meaning of the Operator symbol remains a matter of speculation, though many series employ their own theories to it’s meaning.  Some writers claim it is a simple representing the Slender Man, others claim it to be a ward against him.  The presence of this symbol is often seen as verifcation that a work of fiction is in fact part of the Slender Man Mythos, even if no other signs of haunting have begun.

  The Observer Symbol

Description – A set of 2 circles and two ovals, resembling the shape of an atomic particle with an eyeball as a nucleus.  The two ovals can also be interpreted as eyes.

Origins – TribeTwelve

A symbol representing the antagonist “The Observer” in TribeTwelve.  This symbol is used exclusively by this series: use of the symbol outside of TribeTwelve is not approved by the creator.  It also became the TribeTwelve twitter image after the Observer prevented Noah from changing it by some means.  Animated versions of this symbol frequently appear in TribeTwelve videos.

DarkHarvest Symbol

Description – An operator symbol with an x that more closely resembles a cross, enclosed inside a diamond.

Origins – Dark Harvest

Details later.

  HisCollector Symbol

Description – An emoticon like face, rendered “:>”, often displayed in distrubing contexts, such as drawn in blood in the picture.

Origins – The Angel’s Game

Introduced in The Angel’s Game as the face of a mask and later featured in APCollection/hiscollector, this symbol represents “Mr. Collector” a serial killer associated with the Slender Man.  More details later.

  Benefactor Symbol

Description: An operator symbol with a “cross-out” line drawn through it, in the manner of an anti-symbol.

Origins – compileTRUTH

A symbol used by Dr. Cairo while under the disguise of fearfulxbenefactor.  Depicted as a sort of “anti-operator symbol” to imply Benefactor’s alignment against the Slender Man, the revealtion of the whole thing as a hoax by Cairo proved this symbol ultimately meaningless.

Messenger Symbol (One Bad Dream)

Description: An symbol with three-way-radial symmetry.

Origins – One Bad Dream

A symbol appearing in the “One Bad Dream” vlog, appearing to represent the involvement of Zalgo or his apparent servant, The Messenger.